/*
** file_zip.cpp
**
**---------------------------------------------------------------------------
** Copyright 1998-2009 Randy Heit
** Copyright 2005-2009 Christoph Oelckers
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
**
*/

#include "resourcefile.h"
#include "w_wad.h"
#include "w_zip.h"
#include "ancientzip.h"

#define BUFREADCOMMENT (0x400)

//-----------------------------------------------------------------------
//
// Finds the central directory end record in the end of the file.
// Taken from Quake3 source but the file in question is not GPL'ed. ;)
//
//-----------------------------------------------------------------------

static DWORD Zip_FindCentralDir(FileReader * fin)
{
	unsigned char buf[BUFREADCOMMENT + 4];
	DWORD FileSize;
	DWORD uBackRead;
	DWORD uMaxBack; // maximum size of global comment
	DWORD uPosFound=0;

	fin->Seek(0, SEEK_END);

	FileSize = fin->Tell();
	uMaxBack = MIN<DWORD>(0xffff, FileSize);

	uBackRead = 4;
	while (uBackRead < uMaxBack)
	{
		DWORD uReadSize, uReadPos;
		int i;
		if (uBackRead + BUFREADCOMMENT > uMaxBack) 
			uBackRead = uMaxBack;
		else
			uBackRead += BUFREADCOMMENT;
		uReadPos = FileSize - uBackRead;

		uReadSize = MIN<DWORD>((BUFREADCOMMENT + 4), (FileSize - uReadPos));

		if (fin->Seek(uReadPos, SEEK_SET) != 0) break;

		if (fin->Read(buf, (SDWORD)uReadSize) != (SDWORD)uReadSize) break;

		for (i = (int)uReadSize - 3; (i--) > 0;)
		{
			if (buf[i] == 'P' && buf[i+1] == 'K' && buf[i+2] == 5 && buf[i+3] == 6)
			{
				uPosFound = uReadPos + i;
				break;
			}
		}

		if (uPosFound != 0)
			break;
	}
	return uPosFound;
}


enum
{
	LUMPFZIP_NEEDFILESTART = 128
};

//==========================================================================
//
// Zip Lump
//
//==========================================================================

struct FZipLump : public FResourceLump
{
	WORD	GPFlags;
	BYTE	Method;
	int		CompressedSize;
	int		Position;

	virtual FileReader *GetReader();
	virtual int FillCache();

private:
	void SetLumpAddress();
	virtual int GetFileOffset() 
	{ 
		if (Method != METHOD_STORED) return -1;
		if (Flags & LUMPFZIP_NEEDFILESTART) SetLumpAddress();
		return Position; 
	}
};


//==========================================================================
//
// Zip file
//
//==========================================================================

class FZipFile : public FResourceFile
{
	FZipLump *Lumps;

public:
	FZipFile(const char * filename, FileReader *file);
	virtual ~FZipFile();
	bool Open(bool quiet);
	virtual FResourceLump *GetLump(int no) { return ((unsigned)no < NumLumps)? &Lumps[no] : NULL; }
};


//==========================================================================
//
// Zip file
//
//==========================================================================

FZipFile::FZipFile(const char * filename, FileReader *file)
: FResourceFile(filename, file)
{
	Lumps = NULL;
}

bool FZipFile::Open(bool quiet)
{
	DWORD centraldir = Zip_FindCentralDir(Reader);
	FZipEndOfCentralDirectory info;
	int skipped = 0;

	Lumps = NULL;

	if (centraldir == 0)
	{
		if (!quiet) Printf("\n%s: ZIP file corrupt!\n", Filename);
		return false;
	}

	// Read the central directory info.
	Reader->Seek(centraldir, SEEK_SET);
	Reader->Read(&info, sizeof(FZipEndOfCentralDirectory));

	// No multi-disk zips!
	if (info.NumEntries != info.NumEntriesOnAllDisks ||
		info.FirstDisk != 0 || info.DiskNumber != 0)
	{
		if (!quiet) Printf("\n%s: Multipart Zip files are not supported.\n", Filename);
		return false;
	}

	NumLumps = LittleShort(info.NumEntries);
	Lumps = new FZipLump[NumLumps];

	// Load the entire central directory. Too bad that this contains variable length entries...
	int dirsize = LittleLong(info.DirectorySize);
	void *directory = malloc(dirsize);
	Reader->Seek(LittleLong(info.DirectoryOffset), SEEK_SET);
	Reader->Read(directory, dirsize);

	char *dirptr = (char*)directory;
	FZipLump *lump_p = Lumps;
	for (DWORD i = 0; i < NumLumps; i++)
	{
		FZipCentralDirectoryInfo *zip_fh = (FZipCentralDirectoryInfo *)dirptr;

		int len = LittleShort(zip_fh->NameLength);
		FString name(dirptr + sizeof(FZipCentralDirectoryInfo), len);
		dirptr += sizeof(FZipCentralDirectoryInfo) + 
				  LittleShort(zip_fh->NameLength) + 
				  LittleShort(zip_fh->ExtraLength) + 
				  LittleShort(zip_fh->CommentLength);
		
		if (dirptr > ((char*)directory) + dirsize)	// This directory entry goes beyond the end of the file.
		{
			free(directory);
			if (!quiet) Printf("\n%s: Central directory corrupted.", Filename);
			return false;
		}
		
		// skip Directories
		if (name[len - 1] == '/' && LittleLong(zip_fh->UncompressedSize) == 0) 
		{
			skipped++;
			continue;
		}

		// Ignore unknown compression formats
		zip_fh->Method = LittleShort(zip_fh->Method);
		if (zip_fh->Method != METHOD_STORED &&
			zip_fh->Method != METHOD_DEFLATE &&
			zip_fh->Method != METHOD_LZMA &&
			zip_fh->Method != METHOD_BZIP2 &&
			zip_fh->Method != METHOD_IMPLODE &&
			zip_fh->Method != METHOD_SHRINK)
		{
			if (!quiet) Printf("\n%s: '%s' uses an unsupported compression algorithm (#%d).\n", Filename, name.GetChars(), zip_fh->Method);
			skipped++;
			continue;
		}
		// Also ignore encrypted entries
		zip_fh->Flags = LittleShort(zip_fh->Flags);
		if (zip_fh->Flags & ZF_ENCRYPTED)
		{
			if (!quiet) Printf("\n%s: '%s' is encrypted. Encryption is not supported.\n", Filename, name.GetChars());
			skipped++;
			continue;
		}

		FixPathSeperator(name);
		name.ToLower();

		lump_p->LumpNameSetup(name);
		lump_p->LumpSize = LittleLong(zip_fh->UncompressedSize);
		lump_p->Owner = this;
		// The start of the Reader will be determined the first time it is accessed.
		lump_p->Flags = LUMPF_ZIPFILE | LUMPFZIP_NEEDFILESTART;
		lump_p->Method = BYTE(zip_fh->Method);
		lump_p->GPFlags = zip_fh->Flags;
		lump_p->CompressedSize = LittleLong(zip_fh->CompressedSize);
		lump_p->Position = LittleLong(zip_fh->LocalHeaderOffset);
		lump_p->CheckEmbedded();
		lump_p++;
	}
	// Resize the lump record array to its actual size
	NumLumps -= skipped;
	free(directory);

	if (!quiet) Printf(", %d lumps\n", NumLumps);
	
	PostProcessArchive(&Lumps[0], sizeof(FZipLump));
	return true;
}

//==========================================================================
//
// Zip file
//
//==========================================================================

FZipFile::~FZipFile()
{
	if (Lumps != NULL) delete [] Lumps;
}

//==========================================================================
//
// SetLumpAddress
//
//==========================================================================

void FZipLump::SetLumpAddress()
{
	// This file is inside a zip and has not been opened before.
	// Position points to the start of the local file header, which we must
	// read and skip so that we can get to the actual file data.
	FZipLocalFileHeader localHeader;
	int skiplen;

	FileReader *file = Owner->Reader;

	file->Seek(Position, SEEK_SET);
	file->Read(&localHeader, sizeof(localHeader));
	skiplen = LittleShort(localHeader.NameLength) + LittleShort(localHeader.ExtraLength);
	Position += sizeof(localHeader) + skiplen;
	Flags &= ~LUMPFZIP_NEEDFILESTART;
}

//==========================================================================
//
// Get reader (only returns non-NULL if not encrypted)
//
//==========================================================================

FileReader *FZipLump::GetReader()
{
	// Don't return the reader if this lump is encrypted
	// In that case always force caching of the lump
	if (Method == METHOD_STORED)
	{
		if (Flags & LUMPFZIP_NEEDFILESTART) SetLumpAddress();
		Owner->Reader->Seek(Position, SEEK_SET);
		return Owner->Reader;
	}
	else return NULL;	
}

//==========================================================================
//
// Fills the lump cache and performs decompression
//
//==========================================================================

int FZipLump::FillCache()
{
	if (Flags & LUMPFZIP_NEEDFILESTART) SetLumpAddress();
	const char *buffer;

	if (Method == METHOD_STORED && (buffer = Owner->Reader->GetBuffer()) != NULL)
	{
		// This is an in-memory file so the cache can point directly to the file's data.
		Cache = const_cast<char*>(buffer) + Position;
		RefCount = -1;
		return -1;
	}

	Owner->Reader->Seek(Position, SEEK_SET);
	Cache = new char[LumpSize];
	switch (Method)
	{
		case METHOD_STORED:
		{
			Owner->Reader->Read(Cache, LumpSize);
			break;
		}

		case METHOD_DEFLATE:
		{
			FileReaderZ frz(*Owner->Reader, true);
			frz.Read(Cache, LumpSize);
			break;
		}

		case METHOD_BZIP2:
		{
			FileReaderBZ2 frz(*Owner->Reader);
			frz.Read(Cache, LumpSize);
			break;
		}

		case METHOD_LZMA:
		{
			FileReaderLZMA frz(*Owner->Reader, LumpSize, true);
			frz.Read(Cache, LumpSize);
			break;
		}

		case METHOD_IMPLODE:
		{
			FZipExploder exploder;
			exploder.Explode((unsigned char *)Cache, LumpSize, Owner->Reader, CompressedSize, GPFlags);
			break;
		}

		case METHOD_SHRINK:
		{
			ShrinkLoop((unsigned char *)Cache, LumpSize, Owner->Reader, CompressedSize);
			break;
		}

		default:
			assert(0);
			return 0;
	}
	RefCount = 1;
	return 1;
}


//==========================================================================
//
// File open
//
//==========================================================================

FResourceFile *CheckZip(const char *filename, FileReader *file, bool quiet)
{
	char head[4];

	if (file->GetLength() >= (long)sizeof(FZipLocalFileHeader))
	{
		file->Seek(0, SEEK_SET);
		file->Read(&head, 4);
		file->Seek(0, SEEK_SET);
		if (!memcmp(head, "PK\x3\x4", 4))
		{
			FResourceFile *rf = new FZipFile(filename, file);
			if (rf->Open(quiet)) return rf;
			rf->Reader = NULL; // to avoid destruction of reader
			delete rf;
		}
	}
	return NULL;
}



